In terms of the weighting, EKOS and Forum have a similar weight while Nanos has a heavier weight in the projection. Some readers have wondered why that is, considering that Nanos's poll was taken over a period of four weeks, and so includes a lot of much older data than either the Forum or EKOS polls.

Three things are taken into account when weighting a poll: the sample size, the field dates, and the track record of the polling firm. Nanos has had a very successful track record (though it has participated in fewer elections than either Forum or EKOS, and who knows how Nanos would have done in Alberta in 2012 or British Columbia in 2013 had it participated), and so has a heavier weight.

The model weights each poll on a weekly basis, depending on where a poll lands in the model's weekly blocks of time. If a poll straddles two weekly blocks, it is considered to have been conducted in the block in which the majority of the polling took place. When there are multiple weeks that fit that definition, the most recent one is selected. For that reason, Nanos and EKOS are considered to have been conducted in the same weekly block ending on May 11, while Forum is in the most recent block ending on May 18.

The model is designed this way so as not to put too much importance on differences of a day or two between polls, since the election is so far away and shifts in voting intentions are slow to occur. When the election campaign begins, the model switches over to a daily weighting scheme.

But is it fair to consider the Nanos poll as recent as the EKOS poll, considering its field dates run back to mid-April? On the face of it, it isn't. This is a quirk of the model that is being exposed by Nanos's abnormally long polls (no one else is conducting polls taken over more than a week). During the election campaign, this would not be an issue as no pollster would release such a poll.

So why not consider Nanos an older poll? The guiding principle behind the model is uniformity and objectivity. All polls are handled by the same set of criteria, and no adjustments are made by me. This is what makes it a model in my view - once you stick your thumbs into it based on your gut or intuition, you are just making an educated guess.

I used to weight polls by their median date, rather than by the last day of polling. This was meant to reflect how some polls had older data in them than others, even if they finished polling on the same day. But this had a perverse effect. If I weighted these three polls by their median date, Forum would have been weighted for May 13, EKOS would have been weighted for May 9, and Nanos for May 1. Forum would be considered four days 'newer' than EKOS, despite EKOS leaving the field only one day before Forum did.

It would reward Forum's flash-polls taken over one or two days, and penalize polls conducted over (reasonable) longer periods. The Nanos example is an extreme, but the EKOS example is very relevant. EKOS is polling over a longer period, is less vulnerable to daily blips based on the news-of-the-day, and has the opportunity to call-back people who did not pick-up the first go around. Polls taken over a day or two have no such opportunity, and run a higher risk of being unrepresentative.

Because of this, I abandoned the median-date weighting. But because I apply things uniformly, the Nanos poll is treated as far newer by the model than common sense would dictate.

Five months (to the day) from the next election, this is not a big deal. During the election campaign, no such oddity would be very likely to occur again. In any case, it hasn't had much effect on the projection, which moves slowly this far out from the vote. If the Nanos poll had been weighted for May 1, the median date, the projection would be little different: 31.8% for the Conservatives, 30.3% for the Liberals, and 25% for the NDP.

A shift of 2% is isn't minimal in an aggregate model like the one Eric uses. It's quite telling as the individual data as you've noted shows a much higher rise for the NDP +5% for EKOS and +7% for Forum.

There's just so much other data with lower scores for the NDP keeping those two polls in check. If more polls begin to show the same as Forum and EKOS the Model will slowly change to reflect that.

Is it possible to make a seat projection based on your model that can show seats at different levels of support. If I wanted to see what would happen with the LPC at 20% or the NDP at 35%.

I'm asking because it look like there is a major efficiency issue with the Liberals and a minor one for the CPC. At 25% the Liberal get 56 seats while the NDP would get 90. At 28% the Cons get 100 seas and at the NDP get 105 at 27%, though it does look to revise at high levels of support for the CPC.

They aren't necessarily related. If, for example, the CPC is at its max, the LPC is probably losing a lot of seats to the NDP, so the NDP would not be at its minimum. If the NDP is at its max, the LPC is probably losing a lot of seats to the CPC, so the CPC would not be at its minimum. Etc.

Éric, has Nanos made available to you or anyone else what trend, if any, appeared in their month-long poll? In other words, is there any information about how the figures progressed from one week to the next?

I may be wrong, but the results for the NDP federally are sounding more and more like the NDP in Alberta. First there was a sudden rise in the NDP popularity which nobody really relieved would last and then there was that huge surge at the end that put the NDP in power. The NDP is rising the same way, there is a similar three way split.History may be about to repeat itself federally.

Yes, there are similarities but many differences; the most obvious; Stephen Harper has not been in power for 44 years! Secondly, the CPC is not "institutionalised" in government, politics, finance and culture to the degree the Alberta PC party was and or is. Glen, history may be about to repeat itself or you may end up losing a number of bets and wagers between now and Oct. 19th.

I understand the methodological reasoning behind it but, I think it very unlikely the Greens will take Victoria, I think this a quirk of your methodology putting too much weight upon by-elections. This is a riding that in the Provincial wipe-out of 2001 the NDP still retained 37% of the vote! I think you are over-estimating the Green vote, it may be close come election time but, I feel the NDP still has the advantage.

If the Greens do manage to win Victoria-that will be very bad news for the NDP and I suspect over a 5-15 year period we'll see the Greens replace the NDP as the anti-establishment-protest vote party both in BC and Canada

"This is a riding that in the Provincial wipe-out of 2001 the NDP still retained 37% of the vote!"

2001 was a long time ago. I'd point out it was held by the Liberals federally at the time, and by a very green Liberal. The federal riding actually extends out of Victoria Beacon Hill into Oak Bay Gordon Head which is currently represented by Andrew Weaver, and even in Victoria Beacon Hill the Greens took 33% of the vote their provincially in 2013.

"I suspect over a 5-15 year period we'll see the Greens replace the NDP as the anti-establishment-protest vote party both in BC and Canada"

The model gives the results it gives. It neither stands nor falls on any single riding.

As for the Greens replacing the NDP as the "anti-establishment-protest vote party", I'm fairly sure the NDP are OK with that. They don't want to be just an outlet for protest votes (though they'll take them, of course), they want to form the next government.

The Greens could never hope to replace the NDP, or even compete with them on a serious level. Why? Because they are two very different political parties, with different objectives, and who mostly appeal to different voting constituencies. The NDP is a centre-left, social democratic, labour party with strong institutional links with unions. The Green Party is a sometimes progressive, sometimes conservative environmentalist party whose minimal electoral gains are only a decade old.

The NDP appeals to labour voters, ideologically left of centre voters, environmentalists, activists, recently Quebec nationalists and occasionally protest voters. There is no way that Canada’s labour unions, who are particularly strong in BC, would ever support the Green Party. If anything, their economic policies (income splitting and the Green Tax Shift) are regressive and right of centre. Also, if you look at Canada’s election results over the past decade, most of the Green Party’s minuscule gains have not come from the NDP. When the Greens began to enjoy a small amount of momentum (after 2004), this newfound support was coming from disenchanted Liberal and PC voters, along with traditional nonvoters. The NDP also began to make more impressive gains at the expense of the scandal plagued Liberals during the same period.

Besides committed environmentalists (we’re really talking about a tiny sliver of voters), most Green voters tend to be the completely non-ideological types who are just fed up with the status-quo. Really, those voters are fair game for any party. As we have seen before, they can vote for parties of the Hard Right, Hard Left, Centre, whatever.

The Green Party of Canada is certainly a legitimate party, with some legitimate objectives; however, in all honesty, they face a much lower ceiling than the NDP does. Why? Because as a centre-left party committed to social democracy, the NDP not only has a coherent agenda but can appeal to voter’s pocketbooks. The Greens, on the other hand, not only pander around the political spectrum (income splitting anyone? No, how about child care?), but their platforms always contain measures that will make commodities more expensive for ordinary citizens. There is a very good reason why green parties in Europe never surpass third place. The pinnacle of Green success in Europe has been for these parties to be junior coalition partners to social democrats. In contrast, almost all European countries and most Canadian provinces have had social democratic governments.

I like Elizabeth May, but it is very likely that the Green Party will be a short-lived experiment in Canadian political history; unless, that is, the voting system is changed within the next decade. In that event, the Greens would have a shot at winning a respectable number of seats (but they’ll never get anywhere near power).

What I would like to see is a FPTP Parliament and a PR Senate. That would be an effective way for the Senate to serve the purpose it was originally intended, being a backup to the Parliament, while avoiding the corruption brought on by being an unelected body.

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